Search results for "Reproduction"
showing 10 items of 752 documents
Reproduction et renouvellement des populations (Actes du XIIIe colloque national de démographie)
2009
Chronic Background Radiation Correlates With Sperm Swimming Endurance in Bank Voles From Chernobyl
2022
Sperm quantity and quality are key features explaining intra- and interspecific variation in male reproductive success. Spermatogenesis is sensitive to ionizing radiation and laboratory studies investigating acute effects of ionizing radiation have indeed found negative effects of radiation on sperm quantity and quality. In nature, levels of natural background radiation vary dramatically, and chronic effects of low-level background radiation exposure on spermatogenesis are poorly understood. The Chernobyl region offers a unique research opportunity for investigating effects of chronic low-level ionizing radiation on reproductive properties of wild organisms. We captured male bank voles (Myo…
Editorial: Emerging Chemical Risks for Human Health: Endocrine Disruption by Per- and Poly-Fluorinated Alkyl Substances (PFAS).
2021
First insights into female sperm storage duration in tardigrades.
2022
Female sperm storage is ubiquitous in the animal kingdom and it has been shown to be linked to several evolutionary processes, from postcopulatory sexual selection to dispersal. Here we report, for the first time, long-term sperm storage in females of the tardigrade Macrobiotus polonicus. Females, isolated after a short contact with a male, were able to use the stored sperm for up to 5 weeks (mean of 2 weeks), which translates to a considerable proportion of female post-mating longevity under controlled laboratory conditions (60% on average). Our study provides the first insights into the duration of sperm storage, an underexplored feature of the reproductive biology of tardigrades. Additio…
La Formation et la Reproduction des capacités humaines dans la pensée de Romano Alquati
2022
L’article traite de l’importance assumée par la question de la formation (de la reproduction à la capacité active vivante), dans la dernière période de Romano Alquati. On aborde également le problème de l’appauvrissement de la subjectivité qui, selon l’auteur, serait provoquée par la numérisation des processus d’éducation. The essays deals with the centrality increasingly assumend by the thems of training (the reproduction of active living working capacity) in the last Alquati, as well as the impoverishment of subjectivities that, according to this author, would occur with the digitation of many educational processes.
Effect of temperature rising and ocean acidification on reproductive success of thermophilic sea urchin Arbacia lixula
2012
Modelling the relationship between sexual reproduction and rhizome growth in Posidonia oceanica (L.) Delile
2006
The relationship between flowering and growth performance of Posidonia oceanica (L.) Delile in meadows distributed along the south-eastern coast of Sicily (Italy) was investigated by means of a statistical model (generalized linear mixed model) combined with the lepidochronological analysis. Over a 28-year period, 67 floral stalk remains were observed. The highest flowering index was recorded in lepidochronological year 1998 (10.1%) and the Inflorescence Frequency per age showed a clear decrease corresponding to 15-year-old shoots. The sexual reproductive event had positive effects on rhizome elongation (cm year−1) and leaf production (no. leaves year−1) in the same flowering year, whilst n…
Potential for adaptation to climate change: family-level variation in fitness-related traits and their responses to heat waves in a snail population.
2017
Background On-going global climate change poses a serious threat for natural populations unless they are able to evolutionarily adapt to changing environmental conditions (e.g. increasing average temperatures, occurrence of extreme weather events). A prerequisite for evolutionary change is within-population heritable genetic variation in traits subject to selection. In relation to climate change, mainly phenological traits as well as heat and desiccation resistance have been examined for such variation. Therefore, it is important to investigate adaptive potential under climate change conditions across a broader range of traits. This is especially true for life-history traits and defences ag…
Luokassa luokassa? : miten vanhempien status-tekijät vaikuttavat lasten toissijaiseen sosialisaatioon ja luokittumiseen ensimmäisinä kouluvuosina?
2011
Bourdieu presented his theory of class and class reproduction and I'm interested in founding out how does socialization process affect this dynamic process in an egalitarian western country. Does educational system determine the future of the children by renewing the class structure or does the equal opportunities to succeed academically invalidate the reproduction cycle. By using longitudinal Alkuportaat-data (N=2258) from years 2006-2008 a co-variate analysis and a hierarchical modelling were made. Mathematical problem-solving and fluency in mother tongue were used as indicators for successful secondary socialization. The class structure is presented by parents' socio-economic status, deg…
Impact ofenvironmental variability on year-class strength of Baltic cod (Gadus morhua calliarias L.)
2014
Elektroniskā versija nesatur pielikumus